xref: /aosp_15_r20/external/skia/include/private/gpu/ganesh/GrTextureGenerator.h (revision c8dee2aa9b3f27cf6c858bd81872bdeb2c07ed17)
1 /*
2  * Copyright 2023 Google LLC
3  *
4  * Use of this source code is governed by a BSD-style license that can be
5  * found in the LICENSE file.
6  */
7 
8 #ifndef GrTextureGenerator_DEFINED
9 #define GrTextureGenerator_DEFINED
10 
11 #include "include/core/SkImageGenerator.h"
12 #include "include/gpu/ganesh/GrTypes.h"
13 #include "include/private/base/SkAPI.h"
14 
15 #include <cstdint>
16 
17 class GrRecordingContext;
18 class GrSurfaceProxyView;
19 enum class GrImageTexGenPolicy : int;
20 namespace skgpu { enum class Mipmapped : bool; }
21 struct SkImageInfo;
22 
23 class SK_API GrTextureGenerator : public SkImageGenerator {
24 public:
isTextureGenerator()25      bool isTextureGenerator() const final { return true; }
26 
27     /**
28      *  If the generator can natively/efficiently return its pixels as a GPU image (backed by a
29      *  texture) this will return that image. If not, this will return NULL.
30      *
31      *  Regarding the GrRecordingContext parameter:
32      *
33      *  It must be non-NULL. The generator should only succeed if:
34      *  - its internal context is the same
35      *  - it can somehow convert its texture into one that is valid for the provided context.
36      *
37      *  If the mipmapped parameter is kYes, the generator should try to create a TextureProxy that
38      *  at least has the mip levels allocated and the base layer filled in. If this is not possible,
39      *  the generator is allowed to return a non mipped proxy, but this will have some additional
40      *  overhead in later allocating mips and copying of the base layer.
41      *
42      *  GrImageTexGenPolicy determines whether or not a new texture must be created (and its budget
43      *  status) or whether this may (but is not required to) return a pre-existing texture that is
44      *  retained by the generator (kDraw).
45      */
46     GrSurfaceProxyView generateTexture(GrRecordingContext*,
47                                        const SkImageInfo& info,
48                                        skgpu::Mipmapped mipmapped,
49                                        GrImageTexGenPolicy);
50 
51     // External clients should override GrExternalTextureGenerator instead of trying to implement
52     // this (which uses private Skia types)
53     virtual GrSurfaceProxyView onGenerateTexture(GrRecordingContext*, const SkImageInfo&,
54                                                  skgpu::Mipmapped, GrImageTexGenPolicy) = 0;
55 
56     // Most internal SkImageGenerators produce textures and views that use kTopLeft_GrSurfaceOrigin.
57     // If the generator may produce textures with different origins (e.g.
58     // GrAHardwareBufferImageGenerator) it should override this function to return the correct
59     // origin. Implementations should be thread-safe.
origin()60     virtual GrSurfaceOrigin origin() const { return kTopLeft_GrSurfaceOrigin; }
61 
62 protected:
63     GrTextureGenerator(const SkImageInfo& info, uint32_t uniqueId = kNeedNewImageUniqueID);
64 };
65 
66 #endif  // GrTextureGenerator_DEFINED
67